To add to what Jack says, the video is informative and perhaps misleading. I notice they are determining when to "cutoff" when the batteries are under load. Yes, 12.2V is 50% for AGM, when they are at rest! I wonder why they are not using a Victron BMV to measure SOC instead and perhaps verifying that 50% does eventually level out at 12.2 for the AGM's. The focus on voltage perpetuates a misunderstanding of how to practically determine actual SOC when you are using your batteries in the real world.
That said, I was interested in the Watt hours vs AH comment, and to see that those heated Battleborn batteries get around the "at a ski resort with temperatures well below 32 F, lithium batteries are useless." problem, since you can recharge them the same way you would AGM batteries, while still being arguably more efficient than the AGM's.